Rotary paraxial-cavity reciprocable-core injection mold/injection blow mold system

ABSTRACT

An injection mold/blow mold system having a rotative cavitysystem and a reciprocating core system; the cavity-system includes a rotary manifold fed through an axial sprue in one face of the manifold, the sprue connects through sub-sprues with injection molding cavities paraxially positioned in the opposite face of the manifold. Injection blow molding cavities are positioned between the injection molding cavities, all cavities being equidistant from the axis of the manifold; the core-system reciprocates parallel with the axis of rotation of the manifold to and from the cavity bearing face.

United States Patent [1 1 [111 3,752,625 Van Manen Aug. 14, 1973 ROTARYPARAXIAL-CAVITY 3,121,919 2/1964 Turner 4251249 x RECIPROCABLECOREINJECTION 3,482,284 12/1969 Rees 425/130 MOLD/INJECTION BLOW MOLD SYSTEMFOREIGN PATENTS OR PP C IO S [76] Inventor: Dick T. Van Manen, 25Holiday 1,169,524 12/1958 France 425/242 Harbour, Canandaigua, N.Y.4,522,029 7/1970 Japan 425/130 [22] Filed: Aug. 2, 1971 PrimaryExaminer-J. Spencer Overholser [21] P N 168,284 AssistantExaminer-Michael 0. Sutton Related s Application Data Attorney-John F.McClellan, S1. [63] Continuation-impart of Ser. No. 153,262, June 15,

1971- [57] ABSTRACT [52] U S Cl 425/249 425/451 425/1316 205 Aninjection mold/blow mold system having a rotative 425/116 cavity-systemand a reciprocating core system; the l 5 l 1 Int Cl 329d 2'3/03cavity-system includes a rotary manifold fed through an 58] Fie'ld 245247 axial sprue in one face of the manifold, the sprue con- 425/249 130nects through sub-sprues with injection molding cavi- 45] S 5 6 tiesparaxially positioned in the opposite face of the 6 manifold. Injectionblow molding cavities are positioned between the injection moldingcavities, all cavities being equidistant from the axis of the manifold;the [56] Reerences Cited core-system reciprocates parallel with the axisof rota- UNITED STATES PATENTS tion of the manifold to and from thecavity bearing 2,226,408 l2/l940 Nast 425/130 face, 2,488,786 11/1949Watkins..... 3,012,280 12/1961 Scott et a1 425/245 Claims, 2 DrawingFigures 7 4858 as 9 k 1 A T |l4 T 3 121 I s 5 123 us l d 2%,

72 |25 821 so I2 ROTARY PARAXIAL-CAVITY RECIPROCABLE-CORE INJECTIONMOLD/INJECTION BLOW MOLD SYSTEM This application is a continuation inpart of my copending application for United States Patent, Ser. No.153,262, filed June 15, 1971, for INJECTION MOLD- llNJECTlON BLOW MOLDSYSTEM.

This invention relates generally to plastic molding systems andspecifically to injection molding/injection blow molding systems.

My above-referenced co-pending patent application discloses an axiallyfed cavity-bearing rotary manifold which co-acts with cores whichreciprocate to and from the cavities at an angle to the axis of rotation(typically the cores reciprocate radially to the rotary manifold).

The present system, in contrast, comprises an axially fed cavity-bearingrotary manifold which co-acts with cores which reciprocate to and fromthrough cavities parallel with the axis of rotation.

The objects of the invention set forth in my cpending application alsoapply to the present invention. In general design, both systems aresimple, economical, rugged, compact and accessible for inspection,changeover, adjustment and repair.

Both systems are adapted for separate or for simultaneous injectionmolding and injection blow molding, and for production of parts havingexternal undercut configuration, without the undue cycle prolongationencountered in use of conventional cam-action molds; and both systemscan be adapted, although in different ways, for injectionmolding/injection blow molding using inserts, without cycle interruptionfor loading and/or unloading. In both systems, only axial, symmetricalforces are imposed on hot parisons as they are removed from the molds. I

As to structure, the systems of my co-pending application and of mypresent application can use some of the same components which will bedescribed below, such as the injector unit, including the nozzle forfeeding plastic material into the manifold, and such as parts or all ofthe clamp, the tie-bar assembly, and the mani fold-rotation actuatorassemblies. Additionally, the cores and the cavities, both injectionmolding and injection blow molding, are of similar design.

These similarities are pointed out to indicate the flexibility ofinterchange between the two systems. As will be seen, both systems canbe built in such manner as to use sub-components of certain types ofconventional injection molding equipment if necessary. Particularly, itwill become more apparent that conventional injection molding systemscan be modified in the light of the present invention to adapt them forinjection blow molding also.

The principal difference between my prior disclosed system and thepresent system has been mentioned. There is considerable similarity inthat each employs an axially-fed rotary manifold having molding cavitiesin it. However, in the first invention the cavities open outward fromthe rotation axis, typically along radii, and co-act with one or morecore assemblies which come spondingly reciprocate radially to and fromthe manifold, whereas typically in the present invention the cavitiesare circumferentially spaced on equal radii in an axial face of themanifold with the openings parallel with the rotative axis, and a singlecore assembly coactingly reciprocates to and from the manifold parallelwith the manifold axis.

Each system has its unique advantages; the advantages and other objectsof the present invention will become more apparent on examination of thefollowing description, including the drawings in which:

FIG. 1 is a plan view partly in section of an injectionmolding/injection blow molding system;

FIG. 2 is an elevation of the face of a manifold viewed along 22, FIG.1.

In the drawings, similar parts are designated by similar numerals; thedrawings will now be referred to in detail. r

In FIG. I, and referring in part to FIG. 2 for what is shown there, theinjection molding/injection blow molding apparatus 10 of this inventioncomprises five principal units which are mentioned preliminarily forexposition as follows: I v

The injection unit 12 is a screw feed or other standard plastic-injectorhaving a modified nozzle which is axially shiftable by means to bedescribed;

The manifold unit 14 receives plastic material from the injection unit12 and distributes the material to injection molding cavities disposedin the axial face of the manifold opposite the injection unit;

The clamp unit 16 reciprocates a core-carrying platen which is integralwith it to and from the manifold parallel with the axis of the manifold,selectively engaging the cores with the cavities of the manifold inmolding operations;

The manifold rotator unit 18 angularly positions the manifold so thatthe cavities selectively align for coaction with the reciprocable cores;

The tie bar unit 20 includes also the mounting plate I in which themanifold is rotated by the manifold rotator.

In more detail, the injection unit 12 includes a barrel 22 terminatingin a nozzle 24, a motor 26 driving a pump-reservoir unit 28, and a base30 to which the other parts are mounted by ways 32, 34 lying parallelwith the barrel. The ways permit the nozzle to be slightly advanced ordrawn back in its overlapping engagement inside the manifold, by aconventional control system, not shown. This provision reduces theresidual pressure after a charge of plastic is forced into the manifoldaxial sprue by the action of the conventional screw-feeding,valve-controlled injector mechanism (not shown) within the pumpreservoir unit 28.

During injection, the rounded nozzle-end 36 is advanced and pressureseals against the slightly flatter radius of the female portion 38 ofthe manifold sprue block 40, which is screwed to the manifold axle l5and which slidably couples with nozzle 24.

Injected material passes axially into the manifold through sprue-blockopening 41 into the main sprue 42 and then distributes radially outwardthorugh subsprues 44, 46 into injection molds 48, 50 which arepositioned on a diameter of the manifold at equal radial distances fromthe axially located main sprue.

The injection molds each include a mold nozzle 54, 56, an injectionmolding cavity 58, 60 and may have various conventional features usefulin carrying out the injection molding operation, as, for example,tapered countersink 62, 64 for engagement with tapered collars 66, 68 onthe cores.

Injection blow molds I40, 142 (FIG. 2) are split for ejection of blowmolded parts, the split halves bieng designated as a and b in FIG. 2.The injection blow molds are located diametrically opposite each otheron the same circumference as the injection molds 48, 50. They are spacedin angle halfway between the injection molds, as best shown in FIG. 2.

Each injection blow mold is of the conventional split type so thatundercut parts such as bottles can easily be ejected. The halves of eachinjection blow mold are operable on ways (not shown) by an air system orother appropriate conventional drive (not shown) to open and close, asdictated by the conventional synchronizing control network provided forthe entire system but not described herein.

Mold clamps 70, 72 screwed to the mold face 52 of the manifold securethe injection molds 48, 50 to the mold face. The mold clamps alsoconstitute accessible and appropriately located structure in whichchannels for thermally conductive fluid may be provided if desired, asindicated at 148.

For ease in fabrication, inspection, cleaning, and replacement, themanifold assembly may be further divided. FIG. I shows a preferred, veryrigid and sturdy arrangement in which the manifold axle is integral witha circular oversize flange 74. Flange 74 closely fits in and revolves ina recess 76 which is disposed in the face of bearing block 78 co-axiallywith the axle bore 17. Flange 74 is retained by thrust clamps 80, 82,84, 86, (84, 86 shown in FIG. 2 only) which are screwed to the bearingblock 78.

The mold block 88, of which mold face 52 is a part, is preferablydivided into two parts 88a and 88b, along the midline plane of theradially disposed sub-sprues 44, 46 and the entire assembly detachablyunified by screwing and pinning.

The clamp unit 16 typically includes a hydraulic cylinder 90 (the drivecan be pneumatic or electric if desired), a piston 92 driven by thecylinder, a clamp wayblock 94 affixed to the piston and adapted by holes96, 98, 100, 102 (100, 102 shown in FIG. 2 only), a coremounting platen112 affixed to the clamp way-block, and cores 114, 116, 118, 120 (120not shown but disposed behind 118) secured to the platen by a core clamp122.

Each of the cores has a hollow bore 121, 123, 125 shown, connected witha compressed air system (not shown) through the platen.

The cores are spaced equally on a circumference identical to the moldspacing, so that the four cores engage the four molds simultaneously,the pairing-off being in accordance with the rotative position of themanifold as determined by the manifold rotator 18.

The manifold rotator 18 is made to operate in synchronism with the othersystem operations according to well known principles. It comprises, inthe oscillatory version shown, a hydraulic drive cylinder 124 pivoted atone end by a pin 126 to the bearing block 78. A piston 128 having aclevis end 130 pivotally engages a crank arm 132 which is secured byscrews or other suitable means to the circumference of the manifold axlel5.

Stops 134 and 136 (136 shown in FIG. 2 only), are integrally affixed tothe bearing block 78 in such manner and at such locations that theprotruding portion of the stops-precisely limits the travel of bellcrankarm 132 to 90 sweep. This insures that the cores 114, 116 engage theinjection molding cavities 58, 60 at one extreme of rotation of themanifold unit, and engage the injection blow molding cavities 65, 67 (67shown in FIG. 2 only) at the other extreme, and that the other two cores118, 120 (120 not shown) simultaneously engage the remaining molds ateach position.

In operation, the cores which enter the injection molding cavities eachreceive a parison under the urging of the plastic material by theinjector unit. The injector-unit valve (not shown) then cuts off flowand retraction of the unit reduces injection pressure in the manifold tozero as previously noted. Following this, the cores, carrying the hotparisons, are reciprocated out of the cavities by action of the clamp.

The manifold assembly then rotates to the other extreme of travel,aligning the injection blow mold cavities, which are at this timeclosed, with the parisoncharged cores. The charged cores thenreciprocate through the other half cycle of reciprocation carrying theparisons into the injection blow molds and sealing against the injectionblow mold necks.

Compressed air is then released through the bores of the parisoncarrying cores. While this blow molding operation takes place, the othertwo cores are being charged with parisons in the injection blow molds.

During the outward reciprocation of the cores, the split blow-molds openand the finished parts fall into a suitable-receiver below the system,in the preferred mode of operation. An alternative mode of operation isto open split cavities first and allow the blown parts to retract withthe cores, from which they are then ejected.

According to well-known principles, compressed air passages, not shown,may be provided in the manifold if necessary to eject the product fromthe open blowmolds.

Because of the rigidity of support afforded the beart ing block by thetie bars, which screw into it as well as into the flanged portion of thecylinder 90, rotation of the manifold can be very rapid without undulytwisting the frame. The injector pressure to some degree balances themold injection pressure, and because of the symmetry of the arrangement,rapid opening and closing of the split molds, and rapid accelerations ofthe clamp driven assembly, do not affect alignment of the cores with themolds.

In summary, it can be seen that this is a very simple system, and that amajority of the process carried out with it is identical to injectionmolding,

Only two cores and two cavities can be used, if desired, although thetwo pairs described are preferred, for economy in required manifoldrotative angle. The system is adapted for large-scale embodiment also,with sets of four, eight or more molds being used in accordance with theprinciples of this invention. With reference to the use of largernumbers of molds it should be noted that the injection feed-paths toeach mold can be exactly equal if desired, and that inertial forces dueto rotation of the manifold can be kept exactly equal as to each radialsub-sprue.

It is obvious that clamp stroke length required with this invention isan absolute minimum.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed and desired to be obtained by United States LettersPatent is:

1. Injection blow molding apparatus comprising: rotary manifold meanshaving: means with a central input opening therein, means defining aparaxial injection molding cavity radially spaced from and connectedwith the central input opening, and means defining a blow molding cavityisolated from said central input opening, said blow molding cavity beingcircumferentially spaced from the injection molding cavity and paralleltherewith; core means, means for reciprocating the core means parallelwith the manifold means axis for selective engagement with one of saidmolding cavities, means for rotating the manifold means to select saidcore means engagement, and means for feeding material to be molded intothe manifold means central input opening. V

2. Injection blow molding apparatus as recited in claim 1, wherein saidmeans with a central input opening therein is an axial portion of therotary manifold means and wherein'the central input opening is axial tothe rotary manifold means.

3. Injection blow molding apparatus as recited in claim 2, wherein allsaid defining means define plural said paraxial injection moldingcavities with plural said blow molding cavities circumferentially spacedtherefrom, and wherein plural core means are provided and spaced forengagement with plural said injection'molding cavities and plural saidblow molding cavities selectively according to the rotative position ofthe rotary manifold means.

4. Injection blow molding apparatus as recited in claim 2, wherein themeans for rotating the manifold means comprises: means having anaperture therethrough for rotatively mounting said axial portion,operative means having a portion fixed relative to the apertured meansand a movable portion engaging the manifold means for rotating themanifold means, and

stop means fixed relative to the recessed means for defining a rotativeposition of the manifold means.

5. Injection-blow molding apparatus as recited in claim 4, and secondstop means for defining a second rotative position of the manifoldmeans.

6. Injection blow molding apparatus as recited in claim 4, wherein themeans for reciprocating the core means includes clamp means attached tothe core means and means attached to said apertured means for guidingsaid reciprocation of the core means.

7. Injection blow molding apparatus as recited in claim 2, wherein themeans for feeding material into the manifold means includes nozzlemeans, and wherein means are provided for producing axial movement ofthe nozzle means within the axial opening in the manifold means, therebyaltering the feed of said material within the manifold means.

8. Injection blow molding apparatus as recited in claim 4, wherein themeans for rotating the manifold means comprises additionally a circularportion of the manifold means coaxial with said portion with the axialopening therein, and wherein the means having an aperture therethroughhas additionally a coaxial recess in a face thereof adapted for rotativemounting of said circular portion of the manifold means.

9. Injection blow molding apparatus as recited in claim 3, wherein therespective injection molding cavities are positioned in alternationcircumferentially with the respective injection blow molding cavities.

10. Injection blowmolding apparatus as recited in claim 9, wherein thecircumferential spacing from each respective cavity to the next adjacentsaid cavity is substantially equal.

1. Injection blow molding apparatus comprising: rotary manifold meanshaving: means with a central input opening therein, means defining aparaxial injection molding cavity radially spaced from and connectedwith the central input opening, and means defining a blow molding cavityisolated from said central input opening, said blow molding cavity beingcircumferentially spaced from the injection molding cavity and paralleltherewith; core means, means for reciprocating the core means parallelwith the manifold means axis for selective engagement with one of saidmolding cavities, means for rotating the manifold means to select saidcore means engagement, and means for feeding material to be molded intothe manifold means central input opening.
 2. Injection blow moldingapparatus as recited in claim 1, wherein said means with a central inputopening therein is an axial portion of the rotary manifold means andwherein the central input opening is axial to the rotary manifold means.3. Injection blow molding apparatus as recited in claim 2, wherein allsaid defining means define plural said paraxial injection moldingcavities with plural said blow molding cavities circumferentially spacedtherefrom, and wherein plural core means are provided and spaced forengagement with plural said injection molding cavities and plural saidblow molding cavities selectively according to the rotative position ofthe rotary manifold means.
 4. Injection blow molding apparatus asrecited in claim 2, wherein the means for rotating the manifold meanscomprises: means having an aperture therethrough for rotatively mountingsaid axial portion, operative means having a portion fixed relative tothe apertured means and a movable portion engaging the manifold meansfor rotating the manifold means, and stop means fixed relative to therecessed means for defining a rotative position of the manifold means.5. Injection-blow molding apparatus as recited in claim 4, and secondstop means for defining a second rotative position of the manifoldmeans.
 6. Injection blow molding apparatus as recited in claim 4,wherein the means for reciprocating the core means includes clamp meansattached to the core means and means attached to said apertured meansfor guiding said reciprocation of the core means.
 7. Injection blowmolding apparatus as recited in claim 2, wherein the means for feedingmaterial into the manifold means includes nozzle means, and whereinmeans are provided for producing axial movement of the nozzle meanswithin the axial opening in the manifold means, thereby altering thefeed of said material within the manifold means.
 8. Injection blowmolding apparatus as recited in claim 4, wherein the means for rotatingthe manifold means comprises additionally a circular portion of themanifold means coaxial with said portion with the axial opening therein,and wherein the means having an aperture therethrough has additionally acoaxial recess in a face thereof adapted for rotative mounting of saidcircular portion of the manifold means.
 9. Injection blow moldingapparatus as recited in claim 3, wherein the respective injectionmolding cavities are positioned in alternation circumferentially withthe respective injection blow molding cavities.
 10. Injection blowmolding apparatus as recited in claim 9, wherein the circumferentialspacing from each respective cavity to the next adjacent said cavity issubstantially equal.